Hair cutting apparatus preventing wedging of cut hairs between the cutting comb and the cutting knife of the apparatus



Nov. 26, 1963 B. FUTTERER ETAL HAIR cumuc APPARATUS PREVENTING WEDGING 0F CUT HAIRS BETWEEN THE CUTTING COMB AND THE CUTTING KNIFE OF THE APPARATUS Filed Feb. 21, 1961 Inventors aoda War/1g,- Mass/azu- 7 4 f f vzqr Fig. 2

United States Patent tion Filed Feb. 21, 1961, Ser. No. 90,743 4 Claims. (Cl. 30-43) The invention relates to the special construction of a long hair cutting part for dry shaving apparatuses with two toothed cutting path parts i.e. a stationary part, the so-called cutting comb, and the so-called cutting knife which is adapted to reciprocate and which is resiliently pressed against the cutting comb. The long hair cutting part according to the invention can either be arranged as a direct-cutting head which can be mounted and dismounted on the perforated cutting head of a dry shaving apparatus or can be arranged to be separately switched on or off. As a separate constructional part it is equivalent to a hair cutting machine.

In the case of known long hair cutting parts there is obtained a reliable contact surface and so the possibility of a good sliding action between the two cutting path parts by arranging that the untoothed surfaces, of the back of the comb or knife, adjacent the teeth function as slide paths. With this arrangement there is however the drawback that hairs which have been cut off can get into position between the cutting knife and cutting comb, roll backwards and forwards between cutting comb and cutting knife like a roller, and lift the knife from the comb. The consequence of this is a deterioration of the cutting operation which is not detectable by the naked eye.

On the other hand long hair cutting parts are also known wherein only the toothed surfaces of the two cutting path parts i.e. cutting comb and cutting knife slide on one another, while the untoothed longitudinal surfaces immediately adjacent the toothed sliding surfaces are ofset with respect to the latter. In this way hair remains are certainly prevented from sticking between the cutting path parts and from lifting the sliding parts from one another, but such arrangements are very sensitive to bending of individual cutting teeth which is always possible in itself.

The situation is not altered when the tooth gaps in one of the cutting path parts, possibly the cutting knife, extend beyond the bent edge.

The invention has the object of providing a long hair cutting part which prevents these drawbacks and both avoids hindrance of the cutting operation through hairs which have been cut off and ensures a steady and reliable sliding guidance of the two cutting path parts on one another, not only at the rows of teeth.

According to the invention, when the gaps between the cutting teeth of one cutting path part, preferably the cutting knife, extend to behind the bent edge, then the tooth gaps of the other cutting path part, preferably the cutting comb, terminate in front of this edge in such manner that the longer teeth slide over a portion of their length on the continuous back of the other cutting path part. The hair thus leaves the cutting point directly after it has ben cut off. However if cut-off hairs were to get in position between the cutting surfaces they would then very rapidly fall out again through the deeper tooth gaps. Further, not only do two toothed i.e. discontinuous surfaces slide on one another, but a toothed surface slides on an untoothed i.e. continuous surface of the other which provides satisfactory guidance.

The movable cutting knife is suitably pressed against 3,1 11,755 Patented Nov. 26, 1963 the cutting comb by at least three helical springs which are preferably tapered, one of these springs engaging at a point halfway along the length of the cutting knife while the other two springs are disposed near the outer edges of the cutting knife and symmetrically to the center thereof. This has the advantage that the specifc pressure between cutting comb and cutting knife is equal at any tooth, which ensures an equally good cutting effect over the whole toothed length.

The invention is explained in greater detail hereinafter and an embodiment thereof is described, reference being made to the accompanying drawings wherein:

FIGURE 1 is a cross-section through a long hair cutting part taken along the line 11 of FIGURE 2.

FIGURE 2 is a longitudinal section of the long hair cutting part taken along the line II-II of FIGURE 1.

The housing of the shaving apparatus, indicated by 1, has screwed to it by means of two threaded bolts 4 the two cutting path parts i.e. the stationary cutting comb 2 and the reciprocating cutting knife 3. The movable cutting :nife 3 has a follower or entrainment element 5 by means of which it is driven, for example by the oscillating lever of an oscillating armature motor, and also two elongated apertures 6 with which it is guided on the threaded bolts. The gaps between the cutting teeth 7 of the cutting knife extend considerably further back than the gaps between the teeth 8 of the cutting comb, the points of the teeth '7 of the cutting knife standing back to a certain extent with respect to the cutting comb. The cutting knife is so bent at its toothed surface that a hair 9 which has been cut off can pass into the gap 10 between the cutting parts instead of becoming squashed and lifting the cutting knife from the cutting comb; this happens in such a way that the hair can then fall out as indicated by 9' in FIGURE 1. With this arrangement a sufliciently broad slide path a is provided on the back of the cutting comb on which slide path the teeth of the cutting knife can slide over a portion of their length. In this way all conditions are satisfied for an efiicient cutting action.

In order to ensure a parallel guidance of the cutting knife the edge 11, lying opposite the cutting teeth, of the back of the cutting knife is angled off by the amount of the bend. Three tapered springs 12 introduced into the housing 1 provide the necessary pressure by which the cutting knife is pressed against the cutting comb.

We claim:

1. In a hair cutting apparatus, in combination, a stationary plate-shaped member formed along a front edge portion thereof with closely adjacent teeth extending into said plate-shaped member and being separated by gaps; and a reciprocable plate-shaped member having an edge portion abutting against said front edge portion of said stationary plate-shaped member and being formed in said edge portion with closely adjacent teeth separated by gaps, said edge portions of said members abutting against each other forwardly of a rear contact line and the remainders of said plate-shaped members being spaced from each other in the region rearwardly of said rear contact line, the gaps between the teeth in one of said members extending rearwardly beyond said rear contact line communicating with the space between the remainders of said plate-shaped members so as to prevent wedging of the cut hair and the gaps between the teeth in the other member ending forwardly of said rear contact line so that said other of said members has an uninterrupted surface portion abutting against and engaging said teeth of said one member resulting in a firm guiding of said members relative to each other during reciprocation thereof.

2. In a hair cutting apparatus, in combination, a stationary plate-shaped cutting comb having a front edge portion and a rear edge portion and being formed along said front edge portion thereof with closely adjacent teeth extending into said plate-shaped cutting comb and being separated by gaps; and a reciprocable plate-shaped cutting knife having an edge portion abutting against said front edge portion of said stationary cutting comb and being offset with respect to the remainder of the cutting knife along a line located rearwardly of the ends of the gaps between the teeth in said cutting comb, said cutting knife being formed in said edge portion thereof with closely adjacent teeth separated by gaps extending beyond said line into the remainder of the plate-shaped cutting knife, said cutting knife being formed at a rear edge thereof with a flange projecting toward and engaging said rear edge portion of said cutting comb so that said cutting knife is guided during its reciprocation along uninterrupted surfaces of said edge portions of said cutting comb and whereby due to the extension of said gaps between said teeth in said cutting knife beyond said offsetting line Wedging of cut hairs against said uninterrupted surface, which would lead to an undesirable separation of said edge portions of cutting comb and cutting knife, is positively pre vented since such hairs will escape through the gaps in the cutting knife which extend beyond the offset portion thereof.

3. A hair cutting apparatus comprising, in combination, support means; a plate-shaped cutting comb stationarily mounted on said support means, said cutting comb having a front edge portion and a rear edge portion and being formed along said front edge portion with a plurality of closely adjacent teeth extending into said plate-shaped cutting comb and being separated by gaps; a plateshaped cutting knife mounted on said support means between the latter and said cutting comb and having a front edge portion abutting against said front edge portion of said cutting comb, said front edge portion of said cutting knife being offset with respect to the remainder thereof along a line located rearwardly of the ends of the gaps between the teeth in said cutting comb and said cutting knife being formed in said front edge portion thereof with closely adjacent teeth separated by gaps extending beyond said line into the remainder of said plate-shaped cutting knife, said cutting knife being mounted on said support means for reciprocation in a direction transverse to said teeth and being formed at a rear edge thereof with a flange projecting toward and engaging said rear edge portion of said cutting comb so that said cutting knife is guided during the reciprocation along uninterrupted surfaces of said cutting comb; and spring means mounted on said support means and engaging said cutting knife adjacent said front edge portion thereof for resiliently pressing said front edge portion against said front edge portion of said cutting comb.

4. An arrangement as defined in claim 3 in which said support means is formed with a plurality of cavities spaced in longitudinal direction of said cutting knife from each other, and in which said spring means are constituted by a plurality of tapered coil springs respectively located in said cavities and resiliently engaging said cutting knife adjacent said front edge portion thereof.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A HAIR CUTTING APPARATUS, IN COMBINATION, A STATIONARY PLATE-SHAPED MEMBER FORMED ALONG A FRONT EDGE PORTION THEREOF WITH CLOSELY ADJACENT TEETH EXTENDING INTO SAID PLATE-SHAPED MEMBER AND BEING SEPARATED BY GAPS; AND A RECIPROCABLE PLATE-SHAPED MEMBER HAVING AN EDGE PORTION ABUTTING AGAINST SAID FRONT EDGE PORTION OF SAID STATIONARY PLATE-SHAPED MEMBER AND BEING FORMED IN SAID EDGE PORTION WITH CLOSELY ADJACENT TEETH SEPARATED BY GAPS, SAID EDGE PORTIONS OF SAID MEMBERS ABUTTING AGAINST EACH OTHER FORWARDLY OF A REAR CONTACT LINE AND THE REMAINDERS OF SAID PLATE-SHAPED MEMBERS BEING SPACED FROM EACH OTHER IN THE REGION REARWARDLY OF SAID REAR CONTACT LINE, THE GAPS BETWEEN THE TEETH IN ONE OF SAID MEMBERS EXTENDING REARWARDLY BEYOND SAID REAR CONTACT LINE COMMUNICATING WITH THE SPACE BETWEEN THE REMAINDERS OF SAID PLATE-SHAPED MEMBERS SO AS TO PREVENT WEDGING OF THE CUT HAIR AND THE GAPS BETWEEN THE TEETH IN THE OTHER MEMBER ENDING FORWARDLY OF SAID REAR CONTACT LINE SO THAT SAID OTHER OF SAID MEMBERS HAS AN UNINTERRUPTED SURFACE PORTION ABUTTING AGAINST AND ENGAGING SAID TEETH OF SAID ONE MEMBER RESULTING IN A FIRM GUIDING OF SAID MEMBERS RELATIVE TO EACH OTHER DURING RECIPROCATION THEREOF. 